Process of and apparatus for drying and carbonizing textile fabrics



March I7, 1925.

J. H. WALSH PRQCESS OF AND APPARATUS FOR DRYIVNG AND CARBONIZING TEXTILE FABRICS 4 Sheets-Sheet l Filed ril 7, 1922- March 17, 1925. 1,530,065

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1,530,065 J. H. wALsH PROCESS OF AND APPARATUS FOR DRYING AND CARBONIZING TEXTILE FABRICS 1 7. 1922 4 Sheets-Sheet 5 y /f/Mi 4MM@ 015W.

March 17, 1925.

y J. H. wALsH PROCESS OF AND APPARATUS FOR DRYING AND CARBONIZING TEXTILE FABRICS' 4 Sheets-Sheet 4 Filed 27a ve lgril v, 1922 Patented Mar. 17, 195.

UNITED STATES PATENT OFFICE.

JOSEPH WALSH, OF BOSTON, MASSAUHUSETTS, ASSIGNOR TO JOHNS-MANVILLE, INCORPORATED, F NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

PROCESS O'F AN D APPARATUS FOR DBYING AND CARBONIZING TEXTILE FABRICS.

Application tiled April 7, 1922. Serial, No. 550,538.

To all whom 'it may concern.'

Be'it known that I, JOSEPH H. WALSH, a citizen of the United States of America, and resident of Boston, in the count of Suffolk and State of Massachusetts, ave invented new and useful Improvements 1n Processes of and Apparatus for Drying and Carbonizing Textile Fabrics, 0f which the following is a specification.

This invention relates to the treatment of textile fabrics by reagents and' heat, and comp-rises a process useful, for eirample in drying and carbonizing such fabrics an apparatus for this and other uses.

As a step in the finishing of woolen or other animal-fibre textiles, the material is often subjected to what is commonly known as a carbonizing Atreatment in which vegetable matter, such for example as fragments of burrs, nettles and the like, which have not been removed during the preliminary treatment of the libre, are charred by the application of acid and heat, so that their complete removal may be effected by beating, shaking or blowing out the charred substances. In accordance with one such rocess, the fabric is first moistened with ilute acid, and then the material is subjected to a drying heat to drive out the moisture and concentrate the acid retained in the pores of the fabric to a point such that upon a predetermined furt er temperature increase the desired reaction is attained without destruction of the fabric. The discharge of moisture from the fabric has in many cases been accomplished by the application of heat so intense as actually to boil the moisture from within the fibres, causing disruptive evolution of steam and irre lar concentration of the acid solution wit consequent damage to the quality of the finished material. Successful practice of the treatment requires exactitude in the evaporative and heating stages, without which damage and loss must occur In prior practices of which I am aware the mode of application of heat for the mentioned purposes has been exceedingly wasteful, the fabric usually being baked in tran` sit over very hot heating coils without any serious attempt to provide efficient means for directing the heat against the fabric, to prevent the escape of unused heat, or to control the tem rature or moisture content of the surroundmg atmosphere with any degree of certainty. The total heat wasted in an apparatus of the prior type for handling fabric in commercial quantities is consequently a large and serious item of unnecessary expense in cloth finishing establishments. As usually operated, the treatment is carried out in the open, with no provision against escaping-fumes'damaging to the health of workmen and destructive of machinery and metal fittings. When the cloth has been treated in enclosures, so far as I am aware, no provision has heretofore been made for the positive removal of the vapors from the vicinity of the material, thus causing irregular evaporation and concentration of the reagent and promoting recondensation of the moisture. This has discredited, by irregular results, attempts to guard the health of the operators and save heat by enclosing the place of treatment,

The popular wa of supporting the cloth for treatment is y means of guide rolls causing it'to travel in substantially horizontal runs during drying and carbonizing, in order to apply heat from unenclosed coils. This mode of support necessitates intermediate supporting means to prevent sag ing of the runs into contact with one anot 1er, and makes it necessary to rotate some at least of the guide rolls by mechanical means in order to provide for the proper movement of the fabric. When mechanically driven parts are employed near the drying cloth or in a carbonizing chamber, it is difficult to prevent rapid corrosion of the driving mechanism by the acid fumes evolved. More seriously, the arrangement of the fabric in horizontal runs tends to cause moisture to drip from one run to another, causing spotting and other damage to the material.

In the corbonization of the material little effort has heretofore been made to insure thorough exposure of the interior fibres to the action of the acid. Thus progressive heating of Vthe material 'sometimes fails to produce the carbonizing effects theoretically attainable, which is'at-tribut'able to the formation-of an unbroken coating or crust of intermediate oxidation products which tend to resist the further action of the acid. Reg-` ulated evaporative drying and carefully controlled subsequent heating I find to be necessary to certainty of result and .uniformity of product.

Objects of the resent invention are accordingly to provide a treatment for previously acidulated fabric by which evaporative drying at a predetermined rate proceeds uniformly and without damage, to accomplish the carbonization more rapidly, thoroughly, and uniformly than before; to provide apparatus suitable for carying such process into effect, comprising few mechanically driven parts, and of simple construction and capable of installation in a minimum amount of space; to provide for the discharge of the acid fumes evolved at a remote point; to prevent leaka e of fumes into the work room' to provide or the construction of ex se parts of the apparatus of materials e ective y resisting the action of acid; and to provide for economy of heat supplied by preventing wastage either by radiation from the apparatus or b convection from the apparatus in vaporaden air at unduly high temperatures.

The accompanying drawings illustrate by way of example one embodiment of means suitable for carrying the above objects into effect. In the drawings,

Fig. 1 is a horizontal section through the apparatus taken on the line A-B of Fig. 2, the central portion of the apparatus beinbroken away;

ig. 2 is a longitudinalvertical section on a line such as C-D of Fig. 1;

Fi 3 is a vertical transverse section on the line such as E-F of Fig. 2 5

Fig. 4 is a longitudinal, vertical section through the heating chamber and economizer device on the line tir-H of Fig. 3;

Fig. 5 is a framentary vertical cross section lon the line -N of Fig. 4; and

Fig. 6 is a typical cross section through one of the walls of the enclosing housing ofY the device.

Referring to the drawings, and particularly to Fig. 1, an elongate housing is shown comprisingthe end walls 1, 2 and the side walls 3, 4, this housing also being provided with a roof or cover 5 as indicated in Fig. 2. The walls and roof of this structure are preferably constructed as indicated in Fig. 6 wherein an angle iron 5 is illustrated as constituting a support or stud to which are secured the adjacent ends of slabs 6 forming the sheathin or wall of the housing. These slabs are o acid-resistant and preferably heat-insulating material, for example, sheet asbestos or the substance known commercially as Zasbestos wood. This material comprises in general a composition of asbestos libre together with a cementitious binder with or without a suitable filler all united under heavy pressure to form slabs, boards or other structural shapes useful for the desired pur oses. This housing is divided by a vertlca partition 7 into an evaporative dryer comp-artment 8 and a beatenl and carbonizer compartment 9, respectively. At the upper portion of the wall 1 of the housing an opening or slot 1() is provided for the ingress of the material, suitable guide rolls such as 11 being preferably provided outside the housing for directin the material toward the slot. The opposlte Vend wall 2 is provided with a corresponding slot 12 at its upper part for the egress of the fabric, suitable guide rolls 13 being provided for receiving the fabric as it passes out through the slot 12. One or both of the latter guide rolls may be driven, if desired, to impart tension to the web of material, tending to draw the same longitudinally thro h the housing, and a suitable folding mec anism indicated generally at 14 may be provided for the delivered web. The lower part of the partition 7 is provided with a slot 15 permitting the passage of the web of material from the compartment 8 into the compartment 9.

In the upper art of the compartment 8 a series of gui e rolls 16 is arranged, a corresponding series of rolls 17 being located in the lower part of said compartment. The rolls of the upper and lower series are staggered relatively to each other, and are so disposed that the fabric, in passing over the rolls 16 and under the rolls 17, is caused to lie in a series of substantially parallel runs extending through most of the vertical space in the housing. In the compartment 9, corresponding u per and lower series of guide rolls, 18 an 19, are similarly arran ed, so that the fabric in passing throu such compartment is caused to travel 1n parallel vertical runs in the same manner as in compartment 8. Between certain, at least, of the parallel runs of fabric in the compartment 9, vertically disposed controllable radiating heaters, such as the steam coils 20, are provided, the coils being supplied through the pipe 21 controlled by valve 22 outside the housing. If desired, the roof 5 of the compartment 9 may be provided with an educt flue 23 controllable by means of la damper such as 24.

That portion 3", Fig. 1, of the side wall 3 of the housing which extends along the compartment 8 is somewhat thinner than at other points, as indicated at 3*, and this portion of such wall is provided with vertically disposed series of openings in which are secured the ends of nozzle tubes 25. These tubes extend transversely of the compartment 8 and between the parallel runs of the fabric. Preferably these nozzle tubes are of asbestos-wood or other acid-resistant material are closed at their outer extremities as indicated at 26, and are each furnished with tapering longitudinal air discharge slots 27 widest near partition 3a and arranged at diametrically opposite sides of the tube, and so disposed that air issuing from them is directed against the surface of the adjacent run of material. If desired, the nozzle tubes themselves may also be tapered from their open ends toward their closed extremities.

The end wall l of the housing is extended as indicated at 1b, Fig. l, beyond the side wall 3, forming with the wall 29, and end Wall 28 an auxiliary housing, see Figs. 4 and 5, extending transversely across which is a series of bars 30 and a horizontal partition 43 defining upper and lower preheatingl and heating compartments 31 and 32, respectively. ln the lower part of the lower compartment 32 a transverse horizontal partition 33 serves to support a series of heaters, such as headers 34 to which radiator coils 35 are connected, and provides openings 38 between these headers for the flow of air currents. Coils 35 are supplied with steam by means of pipe 36 controlled by valve 37 outside the housing. The several headers 34 are spaced apart to provide slots 38 through which air from the space 39 beneath the partition 33 may pass upwardly between the several heating coils in the compartment 32.

Resting upon the bars 30 in the preheater compartment 31 is an economizer device, which may consist of a rectangular box comprising the side walls 40, 41, the top and bottom walls 42, 43 respectively, and the end walls 44, 45, (Fig. 4). These end walls are furnished with series of openings in which are secured the ends of open-ended tubes 46, and these tubes penetrate transverse bafiles 57. lVhile the tubes 46 may be of metal or of metal coated with acid-resistant paint or enamel, it is practicable and preferred (in view of the heat-transferring efficiency of the large surface .area presented by such tubes and the rate of motion of the hotter and cooler air and the relatively continuous operation) that the tubes may be formed of acid-resistant or acid-proof material having a relatively small heat-conducting capacity, such as asbestos-wood, without preventing the heat-transferrin eil'ect of the device. The econmizer devlce is of a` width such as to leave a space 47 between the wall 40 thereof and the wall 3a of the housing, which space communicates freely with the lower compartment 32. Heated air from the lower compartment 32 may thus be distributed -substantially uniformly over the entire area of the wall 3 from which the tubes 25 extend, so that all of such tubes may be supplied with air under substantially uniform pressure. The space 47 is closed at its top by a horizontal partition 48, and the upper portion of the compartment 8 of the main housing communicates with the space above the economizer device by means of slots or openings 49, (Figs. 1 and 4). It is thus possible for spent and heated air from the drying compartment 8 to pass into the space above the economizer device and to flow longitudinally of the upper part of chamber 31 into the space 50 between the wall 28 and the end member 45 of the economizer device. From the space 50 the exhausting air passes freely through the economizer tubes into a corresponding space 5'1 at the opposite end of the economizer device. This latter space communicates, by means of a duct 52 controlled by damper 5,3, with an exhaust fan 54, such fan delivering the moisture and acid-laden fumes through a pipe 55 to any desired point of discharge. Desirably, by this arrangement, the spent air is under negative pressure within and beyond the economizer device.

At that end of the economizer device adjacent to the fan 54 a suitable inlet opening 56 is provided whereby fresh air may be admitted to the interior of the economizer box and into the space surrounding the tubes 46, to pass longitudinally of the economizer device while contacting with the outer surfaces of the tubes and in the tortuous path compelled by the baffle plates 57. The heating compartment 32 is closed at one end by a vertical partition 58 (Fig. 4) which serves to define a chamber 59 communicating with the intake of a fan 60. This fan, by means of a'conduit 61, lserves to deliver air into the space 39 beneath the radiator headers.

The space within the economizer device surrounding the tubes communicates with the chamber 59 through an opening 62, controlled by a sliding damper 64. The spentair space 50 at the end of the economlzer device also communicates with the chamber 59 by means of an o nin 63, also controlled by the damper 64, w ich t us provides means to vary simultaneously and oppositely the relative areas of the openings 62 and 63, at will.

In operation, in the form shown, the web of fabric enters through the opening 10 and passes in vertical runs over and under the guide rolls 16 and 17 in the drying chamber 8 where it is subjected in a constantlyrenewed and relatively homogeneous atmosphere to the action of the incoming blasts of heated air emerging from the slots in the nozzle pipes 25. The heat of the incoming air, having regard for the humidity of the induct air, the rate and pressure of the blasts, and the speed of the wet web of material, or any of these factors, may be so regulated that as the fabric leaves the drying chamber through the opening 15 in the partition 7 it is substantially dry. As the dried fabric traverses in repeated vertical runs the carbonizing chamber 9, it

is subjected in a comparatively still atmosphere to the action of radiant heat from the heatin coils 20, and is thereb gradually raise to a temperature su cient to cause carbonization of the vegetable matter. It fwill be noted that in passing throu h the chamber 9 the fabric is reeately and alternately subjected to the igh atmospheric temperature existing in the upper part of said chamber and to the temperature in the lower part thereof, while perature for the reaction by the acld con.

centrate formed by the drying operation, at the same time breakin up or cracking any incrustation upon t e libres which might protect their vegetable impurities from the action of the heat; and thus securing uniform, rapid and thorough carbonization of such vegetable material as may be incorporated in the fabric. By the use of the damper 24 and the controllable heating coils 20 the temperature in the carbonizing chamber may be accurately regulated. During the traverse of the fabric through the dryin and carbonizing chambers, the fans 54 and 60 are operated, the fan 54 serving to withdraw the moisture and acid-laden air from the drying chamber through the openings 49, causing the air to pass longitudinally through the economizer tubes and discharging it through the educt ipe 55. At the same time the fan 60 draws resh air in through the opening 56, the fresh air passing repeatedl f over the tubes in and longitudinally o the economizer device and in heat-transferring relationshi to the spent air within the tubes 46, and eing delivered for further heating into space 39, thence passin through the radiator coils 35 and throng the nozzle tubes 35 into the drying chamber 8. For controlling the admission of fresh air the damper 64 may be manipulated, it being evident that if this damper be placed to close the opening 62 no fresh air will be admitted to the apparatus, in which event the air' from the dr ing chamber will merely be circulated t rough the apparatus` passing from the space 50 into the chamber 59, and from thence to the radiator coils for reheating. In this case fan 54 is stopped or slowed. If, on the other hand, it be desired that none of the air be recirculated, the dam er 64 may be ositioned entirely to close t e opening 63.

vidently, by arranging the damper at intermediate positions any desired mixture of fresh air and of the moisture-laden air from the chamber 8 may be admitted to the fan 60 for recirculation in the dr ing chamber. In either adjustment, it will7 be observed that the use of two blowers, (of which fan 60 causes positive internal pressure in chambers 39, 32, 47; and fan 54 causes negative internal pressure in chambers 8, 50, and 51) enables the relative speeds to be so adjusted as to control the pressure in chamber 8 within delicate limits. Desirably, this ressure is normali slightly negative, and this avoids leakage o fumes.

While in the above description a specific series of ste s of the method and one arrangement o the various heating, circulating and economizer devices has been described, it is to be understood that the invention is not restricted to the recommend ed steps or to the s ecifc arran ements, ma terials or devices ut that various changes and modifications may be made without departing from the s irit of the invention. For example, any esired number of the guide rolls 16, 17 may be driven independently of the cloth, or the distribution of the blast tubes 25, the form of the radiating heater 20; or other dispositions of the apparatus may be changed within this disclosure, as will be obvious.`

I claim:

1. Apparatus for carbonizing acidulated fabric comprising a heat-insulated housing, and means Within said housing whereby a web of fabric moved through the housing may be subjected successivcl to the action of a desiccating air blast andywithout intervening cooling to radiant heat in a substantially quiet atmosphere.

2. Apparatus for cloth finishing having therein a heat-insulating housing and means for entering and passing moist cloth through the housing, in combination with means for heating and means for inducing and delivering a number of currents of the heated air against the surface of runs of the cloth. within said housing, and means within said housing acting on the cloth so treated to further raise its temperature by the action of radiant heat.

3. Apparatus for use in cloth finishing comprising a housing having acid resistant walls-: I carbonizing means within said housing, means for heating the fresh air, means for inducing the flow of fresh air into said housing and means for conducting air laden with acid fumes from said housing, means for heating the fresh air.

4. Apparatus for use in carbonizing fabric comprising a heat-insulated housing, means within said housing for raising previously acidulated fabric to a carbonizing temperature, means for inducing the flow of fresh air into a part of said housing,

means for heating such air, delivery nozzles for discharging the heated air against the fabric, and means for conducting the moisture and acid-laden air away from said part of the housing.

5. Apparatus for use in the drying and carbonizing of textile webs comprising an acid-resistant housing having therein means for drying a previously acidulated fabric, means for raising said fabric to a carbonizing temperature, and an exhaust fan for withdrawing air laden with evaporated moisture from the housing.

6. Apparatus for use in the dryin of material from which fumes are evolve during the drying process, comprising a housing, means within such housing for directing blasts of heated air transversely against the material to be dried, a controllable educt passage-leading from said housing, and an exhaust fan communicating with said passage for withdrawing fumedaden air from the housing.

7. Apparatus of the class described comprisin` a housing having a partition wall provi ed with an opening for the passage of a web of fabric, means arranged upon one side of said partition for subjecting a web of fabric passing therethrough to the action of heated fresh air, and means upon the other side of said partition for subjecting the fabric to the action of radiant heat in a relatively still atmosphere.

8. Apparatus for use in the finishing of textile fabrics comprising a housing having means for supporting a previously acidulated fabric web therein, means whereby currents of heated air may be caused to impinge upon opposite surfaces of such material, and means for thereafter subjecting such material to the action of radiant heat. i

9. Ap aratus for use in the finishing of textile abrio comprising a heat-insulated housing, means for discharging blasts of heated air therein, means for supporting and moving a web of fabric transversely of the direction of said blasts, whereby such web acts as a balfle to divert such blasts laterally of the direction of discharge, and heating coils for imparting a carbonizing temperature to fabric passing from the action of said blasts. Y

10. A carbonizing device for treating webs of textile fabric comprising a housing, means within such housing for so supporting the web to be treated as to provide a series of substantially parallel and vertical runs, means for causing heated air to flow in contact with certain of said runs for removing moisture therefrom, and means for subjecting other of such runs to the' action of radiant heat.

11. Apparatus for carbonizing textile fabric comprising a housing having a partition dividing the same into two compartments, said partition havin an opening for the passage of a. web o? fabric therethrough, guide rolls in each o said compartments for supporting and gui ing a fabric web in a series of vertical runs, means in one of said compartments for subjecting a web traversing the same to the action of blasts of heated air, and a series of heating coils in the other of said compartments for subjecting the web guring passage therethrough to radiant eat.

12. Ap aratus for use in the linishing of textile fa ric comprising a housing having a plurality of compartments, a plurality of guide rolls arranged in upper and lower series, respectively, in each of said compartments whereby a web of fabric may be caused to travel in a series of substantially parallel, vertical runs from one side of the ousin to the other and successively throng said compartments, means for ad mitting blasts of heated air to the first of said com artments, and a plurality of vertical ban s of heating pipes arranged to extend between parts only of the. several runsl of fabric in the other compartment.

13. Apparatus for use in carbonizing fab. ric which comprises a housing having therein means for successively subjecting the fabric to the action of a heated current of air and to direct radiant heat, and means for preheating the air entering said housing by passing it in heat transferring relationship to air discharged therefrom.

14. Apparatus flir use'n the finishin of textile fabric which comprises a close chamber having means therein for supportin the fabric to be treated, means for admitting heated air to such chamber and for directing such air against opposite surfaces of the fabric, means whereby such air, after contact with the fabric, may be removed from the chamber and passed in heat transferring relationship to incoming air on` its way to the chamber, and means for thereafter subjecting the fabric to a carbonizing temperature.

15. Apparatus for use in the ing of webs of material, comprising an e ongate, substantially air-tight housing, having ide means therein for supporting a web in a series of parallel runs, air dehve means,whereby blasts of air may be 'd1- rected against such runs, an air h eating chamber having heating coils thereinkan economizer device, a fan for withdrawing warm and fume-laden air from the housing and through the economizer device, and a second fan for drawing fresh air in through the economizer device for discharge into the heating chamber for heatin prior to its discharge through the air elivery means.

16. Apparatus of the class described comprising a housing having means for supporting the material to be dried, a heating chamber having radiator coilstherein, an economizer device su erlpsed u n sald heating chamber, a p ura 'ty of charge pipes each leading from the heatin 'chamber into proximity to the materia to be dried, a controllable passage leading from the economizer device and extendin below the heating chamber, and a fan 1n said passage for drawing fresh air in through the economizer device and delivering it through said passage to the lower part of the heating chamber.

17. An apparatus of the class described comprising a housing having therein means for supporting material to be dried, a heat-` ing chamber, blast nozzles commnicating with said chamber for delivering heated air against the material, an economizer device, means for causing fresh air to enter said economizer device and for causing warm and moisture-laden air from the housing to pass outwardly through said economizer device in heat transferrmglrelation to the incoming air, and means whereby a regulable mixture of such fresh and moistureladen air may be admitted tothe heating chamber. u

18. An appartus for use in the drying and carbonization of textile webs comprising an elongate housing having therein means for guiding a web 1n a series of vertical runs, air discharge means arranged to deliver blasts of air between certain of said runs, heating coils' arranged between other of said runs, a secondary housing having upper and lower compartments, radiator coils in the lower compartm'ent, economizer tubes in the ulper compartment, means for admitting fre air to the economizer complartment, means for admitting warm air om the housing to the interiors of the economizer tubes, a fan for delivering air to the heating compartment, controlling means constructed and arranged to admit regulable'mixtures of fresh air from the economizer compartment and of warm air on its way to the economizer to the intake of the fan, means whereby air from said lower compartment is conducted to the air discharge means, and a second fan for inducing the llow of warm air from the housoutwardly through the economizer u es.

19. Apparatus of the class described comprising a housing having means for supporting and guiding a web of acidulated abrio, means for directing blasts of heated air Vagainst such web, carbonizing means, and an economizer device for preheating such air, said device comprising a series of acid-resistant tubes over which such air is drawn, and through which warm and moisture-laden air is expelled from the housin 20. in economizer device for use in apparatus for treating acidulated materials such as textiles, comprisin a chamber having air-current induct and educt openings and walls of acid-resistant material, a series of open-ended parallel tubes of asbestos-Wood havingtheir ends seated in openings in opposite walls of said chamber respectivel and comprising a flow passage for anot er air-current, and means for inducing flow in the said air-current passages respectively of fume-laden heated air and fresh entering air.

Signed by me at Boston, Massachusetts, this twenty-eighth day of January, 1922.

-JOSEPH H. WALSH.

prising a housing having means for supporting the material to be dried, a heating chamber having radiator coilsltherein, an economizer device su er osed u on said heating chamber, a p ura 'ty of ischarge pipes each leading from the heatin 'chamer into proximity to the materia to be dried, a controllable passage leading from the economizer device and extending below the heating chamber, and a fan 1n said passage for drawing fresh air in through the economizer device and delivering it through said passage to the lower part of the heating chamber.

17. An apparatus of the class described comprising a housing having therein means for supporting material to be dried, a heating chamber, blast nozzles communicating with said chamber for delivering heated air against the material, an economizer device, means for causing fresh air to enter said economizer device and for causing warm and moisture-laden air from the housing to pass outwardly throu h said economizer device in heat transferrmgXrelation to the incoming air, and means whereby a regulable mixture of such freshy and moistureladen air may be admitted Atothe heating chamber.

18. An appartus for use in the drying and carbomzation of textile -webs comprising an elongate housing having therein means for guiding a web 1n a series of vertical runs, air discharge means arranged to deliver blasts of air between certain of said runs, heating coils' arranged between other of said runs, a secondary housing having upper and lower compartments, radiator coils in the lower compartment, economizer tubes in the u per compartment, means for admitting fregi air to the economizer compartment, means for admitting warm air rom the housing to the interiors of the economizer tubes, a fan for delivering air to the heating compartment, controlling means constructed and arranged to admit regulable mixtures of fresh air from the economizer compartment and of warm air on its way to the economizer to the intake of the fan, means whereb air from said lower compartment is con ucted to the air discharge means, and a second fan for inducing the flow of warm air from the housing outwardly through the economizer tu es.

19. Apparatus of the class described comprising a housing having means for supporting and guiding a web of acidulated abric, means for directing blasts of heated air against such web, carbonizing means, and an economizer device for preheating such air, said device comprising a series of acid-resistant tubes over which such air is drawn, and through which warm and moisture-laden air is expelled from the housin 20. in economizer device for use in apparatus for treating acidulated materials such as textiles, comprisin a chamber having air-current induct an educt openings and walls of acid-resistant material, a series of open-ended parallel tubes of asbestos-wood having their ends seated in openings in opposite walls of said chamber respectivel and comprising a iow passage for another air-current, and means for inducing 'low in the said air-current passages respectively of fume-laden heated air and fresh entering air.

Signed by me at Boston, Massachusetts, this twenty-eighth day of January, 1922.

-JOSEPH H. WALSH.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,530,065, granted March 17, 1925, upon the application of Joseph H. Walsh, of Boston, Massachusetts, for an improvement 1n Processes of and Apparatus for Drying Carbonizing Textile Fabrics, follows heating the resh air,"; and that the said Letters an error appears in the printed specification requiring correction as Pa e 4, l1ne 120, claim 3, strike out the words and comma means for Patent should be read with this correctlon therein that the same may conform to the record of the case in the Patent Oilice.

Signed and sealed Athis 7th day of April, A. D. 1925.

[SEAL] KARL FENNING, Acting Uommz'ssoner of Patents.

Certicate of Correction.

It is hereby certified that in Letters Patent No. 1,530,065, granted March 17, 1925, upon the application of Joseph H. Walsh, of Boston, Massachusetts, for an improvement in Processes of and Apparatus for Drying Cerbonizing Textile Fabrics, an error appears in the printed specification requiring correction as follows: Pa e 4, line 120, claim 3, strikeI out the words and comma means for heating the resh airf; and that the said Letters Patent should be read with this gnrection therein that the same may conform to the record of the case in the Patent Signed and sealed this 7th day of April, A. D. 1925.

[SEAL] KARL FENNING,

Acting Uommssoner of Patents. 

